Protein adsorption onto monoliths: A surface energetics study

Abstract

This part of work was done to explore the basic understanding of the adsorption chromatography by determining the interaction of selected model proteins (n = 5) to monolithic chromatographic materials, with varying densities of butyl and phenyl ligands. Surface energetics approach was applied to study the interaction behavior. The physicochemical properties of the proteins and monolithic chromatographic materials were explored by contact angle and zeta potential values. These values were used to study protein to monolith interaction under various operating conditions. Surface energetics approach allowed the calculation of interaction energy as a function of distance, i.e. energy minimum values. Calculations were performed at various conditions to analyze the effect of major operating parameters on the interaction strength. The interaction strength exposed the hydrophobic nature of the monoliths which increases with increasing ligand density. Further, interaction energy of proteins were higher with monolith with butyl ligand compared to monolith with phenyl ligand. For instance, lactoferrin interaction to monoliths with butyl represents more interaction, i.e. 24.38 kT as compared to monoliths with phenyl i.e. 23.28 kT, keeping lambda as 0.2 nm and salt concentration as 100 mM of ammonium sulphate. Hence, more energy and time will be consumed for elution of proteins immobilized to monoliths with butyl. Similarly, the effect of solid surface for proteins immobilization, effect of ligand density and effect of lambda showed some interesting insights on the interaction behavior. The knowledge generated from the present work will help in the basic understanding as well as development of an efficient, low cost downstream processing design and may mimic the real chromatographic experiments.

Comparative analysis of the methods used for finding surface energy to investigate protein interaction behavior on chromatographic supports

“…These values are derived from the association constants (calculated by isothermal titration calorimetry (ITC) . A recent study from our group has calculated the interaction energies for protein to monolithic chromatographic supports in a similar range . Another ITC study reports adsorption energy for trypsinogen and α‐chymotrypsinogen A to various hydrophobic adsorbents in −0.40 kT to −3.23 kT at various densities of butyl ligand …”

“…This approach calculates the interaction energies as per extended Derjaguin, Landau, Verwey, and Overbeek (DLVO) theory . It has also been employed to study interactions of proteins to monoliths . The interactions energy between a protein and a chromatographic bead is the sum of Lifshitz–van der Waals (LW), acid–base (AB), and electrostatic (EL) energies as shown in Equation 1. …”

“…[25][26][27][28] It has also been employed to study interactions of proteins to monoliths. 29 The interactions energy between a protein and a chromatographic bead is the sum of Lifshitz-van der Waals (LW), acid-base (AB), and electrostatic (EL) energies 30 as shown in Equation 1.…”

Understanding the interaction of proteins to ion exchange chromatographic supports: A surface energetics approach

“…This method can discriminate between the chromatographic supports with different base material 31 and ligands 32 in hydrophobic interaction chromatography. Similarly, the said approach has been used to explain the interaction of proteins to monoliths 21 . A recent study is published that explains a comparison of different methods used for the determination of surface energies of colloidal particles 20 .…”

“…15 Several other attempts have been reported to reduce the associated challenges. Thermodynamics approach, 16 Sogami-Ise, 17 adsorption, 18 DLVO and XDLVO (extended Derjaguin, Landau, Verwey, and Overbeek) approach [19][20][21] are few among the applied strategies.…”